The world changed on September 11, 2001, and again on October 4, when the first case of inhalational anthrax in the United States raised worldwide fears of bioterrorism. Although the threat of bioterrorism in Australia has been assessed as low,1 defence and civil authorities had upgraded preparations before the 2000 Olympics.2 Those plans, coordinated by Emergency Management Australia, provided a basis for responses by state emergency services, health services and postal services to the numerous false alarms, "white powder" incidents and hoaxes that followed the US events. No anthrax spores or human anthrax cases associated with these incidents have been detected in Australia, but understandably they have caused considerable public anxiety. In retrospect, it now appears that the anthrax-containing letters in the US were probably of domestic origin, with no targets outside that country.3

After the US incidents, health departments were swamped with calls from the public asking what had been done to protect them. They wanted to know how to protect themselves, and whether they needed antibiotics, vaccines for anthrax or smallpox, or gas masks. Health authorities emphasised communication to reassure those who were worried, as well as to provide authoritative information and planning advice about anthrax and other conceivable threats. Should a biological incident ever occur in Australia, communication would be even more important, not only in managing the emergency, but also in minimising community alarm, which could cause more damage than the biological agent itself. In any incident, healthcare agencies would play a key role in recognising resulting illnesses and managing the health consequences.

The anthrax threat has highlighted the importance of multidisciplinary approaches to biological emergencies. Security intelligence must be wedded to health intelligence, and the lessons learned from past disaster management appropriately applied. As an editorial in the Lancet recently said, "Appropriate reaction to such deliberate attacks, but also to any other emerging epidemic, by a well-organised and well-functioning public health system requires preparedness at all times on all levels".4 Australia's federal system requires close collaboration between the Commonwealth, States and Territories. Emergency service responses are coordinated by Emergency Management Australia. Public health agencies work with emergency services in the States and collaborate through the Communicable Diseases Network Australia and the Public Health Laboratory Network to coordinate national reporting, surveillance, laboratory diagnosis and public health responses for communicable disease outbreaks. Biosecurity planning in Australia has built on these existing disease and disaster surveillance systems.2

Recently, these networks have collaborated to revise training schedules and case definitions to support the earliest possible recognition of any event resulting from deliberate release of a biological agent. Health authorities, through the Communicable Diseases and Public Health Laboratory networks and the network of Chief Health Officers of the States, have also strengthened their linkages with Emergency Management Australia, the federal department of Defence and other government agencies.

Anthrax: The review of Australia's policies has adapted advice from the US Centers for Disease Control and Prevention (CDC), World Health Organization (WHO) and United Kingdom Public Health Laboratory Service for local needs. Guidelines for anthrax treatment and post-exposure prophylaxis have been developed by public health physicians, microbiologists and infectious disease specialists, and endorsed by Australia's Chief Health Officers and directors of public health services.

It has been agreed that primary care providers should not prescribe chemoprophylaxis in the event of suspected anthrax. Instead, they should immediately contact their local public health unit for advice about referral for diagnosis and further management (contact details for State and Territory health authorities are available on Fact sheet — anthrax <http://www.health.gov.au/pubhlth/strateg/communic/factsheets/anthrax_fact.htm>). To minimise inappropriate antibiotic use, general practitioners should not provide individuals with a contingency supply of antibiotics for prophylaxis.

State and Territory health authorities are ensuring that there are adequate supplies of appropriate antibiotics in case of an emergency, and the Commonwealth Government is working with pharmaceutical companies to ensure continuity of supply. Anthrax vaccine is not currently registered for use in Australia and is not recommended as a first-line response to an anthrax incident.

Smallpox: The US government's intention to procure 250–300 million doses of smallpox vaccine for mass vaccination appears to have been modified after expert advice. Existing vaccine is effective but has significant adverse effects. The calf-lymph-derived live smallpox vaccine used in the WHO smallpox eradication program is associated with a post-vaccinal encephalitis rate of 3–4 per million primary vaccine doses.5 Forty per cent of encephalitis cases are fatal, and some survivors have permanent neurological deficits. Progressive vaccinia occurs among those who are immunocompromised. WHO guidance is that, given the substantial risk of adverse events after vaccination, mass vaccination of populations is not recommended when there is little or no real risk of exposure.

Despite the stated intention of the US to develop a new vaccine supply against a possible bioterrorism incident, no country is planning to give smallpox vaccine routinely to its citizens. Smallpox is not transmissible until the onset of rash, when the individual becomes ill and is likely to be confined to bed. This provides the rationale for measures to contain any outbreak: after the first cases are identified and isolated, contacts are vaccinated; vaccination prevents or ameliorates disease, even when it is undertaken after exposure to the virus.5 Thus, both WHO and CDC recommend an approach which involves early case detection and post-exposure vaccination with a view to "ring fencing" any outbreak.5-7

Australia has no smallpox vaccine available at present. As a precautionary measure, the Commonwealth Government has arranged with international agencies to secure access to vaccine in the unlikely event of a smallpox incident; arrangements have also been made to secure supplies of vaccine to be held in Australia. If smallpox were introduced into Australia, we would then be in a position to implement a strategy of surveillance, quarantine and vaccination. WHO has pledged support to any country in which an incident occurs, as this would constitute an international emergency. WHO will help countries pool resources to contain any outbreak as rapidly as possible.

Conclusions: Although the risk to Australia is regarded as low, we need to be prepared for a bioterrorism incident. Australia's strong public health infrastructure forms the basis for an effective response to any such incident. While much of the initial planning has focused on anthrax and smallpox, progress has been made on public health and clinical protocols for other potential bioterrorism agents. No public health or security system can guarantee complete safety from bioterrorism attack, but Australia's public health expertise will ensure that harm to the community is minimised.

For the assistance of doctors, a comprehensive guide for dealing with patient inquiries is available on the website of the Commonwealth Department of Health and Ageing (<http://www.health.gov.au/pubhlth/strateg/bio/index.htm>). This also contains a list of contacts for public health authorities around Australia. Relevant information can also be accessed through the WHO and CDC sites (<http://www.who.int/emc/deliberate_epi.html> and <http://www.cdc.gov>, respectively).